Model study on mixing and mass transfer in ferroalloy refining processes

An experimental study has been performed to investigate the bath mixing int ensity induced by a high-strength submerged gas injection in a bottom blown air-stirred one-seventh water model of Creusot-Loire Uddeholm (CLU) reacto r using three different tuyere configurations. Experimental results have be en discussed in terms of the mass transfer rate and mixing time. The air fl ow rates varied from 0.00599 to 0.01465 m(3)/s. The mixing time was determi ned at various gas flow rates, bath heights, and nozzle orientations, both in the presence and absence of a second phase. The mixing time was found to decrease with increasing gas flow rate and decreasing bath height. The inf luence of bath mixing intensity on mass transfer between metal (water) and slag (paraffin) was studied by measuring the transfer of benzoic acid from the gas-stirred water bath to paraffin as a function of the gas injection p arameters. The bath mixing intensity was characterized by the value of the mass transfer rate constant. The rate constant of mass transfer between the metal and slag was found to increase with increasing gas injection rate an d decreasing bath height.